Genotyping of benzimidazole-resistant and dicarboximide-resistant mutations in Botrytis cinerea using real-time polymerase chain reaction assays.
Botrytis cinerea, an economically important gray mold pathogen, frequently exhibits multiple fungicide resistance. A fluorescence resonance energy transfer-based real-time polymerase chain reaction assay has been developed to detect benzimidazole- and dicarboximide-resistant mutations. Three benzimidazole-resistant mutations-(198)Glu to Ala (E198A), F200Y, and E198K-in beta-tubulin BenA were detected using a single set of fluorescence-labeled sensor and anchor probes by melting curve analysis. Similarly, three dicarboximide-resistant mutations-I365S, V368F plus Q369H, and Q369P-in the histidine kinase BcOS1 were successfully distinguished. Unassigned melting profiles in BenA genotyping assay resulted in the identification of a new benzimidazole-resistant BenA E198V mutation. This mutation conferred resistance to carbendazim as do E198A and E198K mutations. The isolates with BenA E198V mutation showed a negative cross-resistance to diethofencarb, but to a lesser extent than the E198A mutants. A survey of 210 B. cinerea field isolates revealed that most of benzimidazole-resistant isolates possessed the E198V or E198A mutation in the BenA gene, and the I365S mutation in the BcOS1 gene was also frequently observed in Japanese isolates. However, benzimidazole-resistant isolates with BenA F200Y or E198K mutations, which confer the diethofencarb-insensitive phenotype, were rare. Our BenA and BcOS1 genotyping is a rapid and reliable method that is suitable for monitoring the fungicide-resistant field population.
Banno
Shinpei
S
Plant Function Research Center, Toyo University, Itakura, Gunma, Japan.
Fukumori
Fumiyasu
F
Ichiishi
Akihiko
A
Okada
Kiyotsugu
K
Uekusa
Hidetoshi
H
Kimura
Makoto
M
Fujimura
Makoto
M
D001483:Base Sequence; D001562:Benzimidazoles / Q000494:pharmacology*; D020171:Botrytis / Q000235:genetics*; D018553:Cucumis sativus / Q000382:microbiology; D004271:DNA, Fungal; D026141:Drug Resistance, Multiple, Fungal / Q000235:genetics*; D005659:Fungicides, Industrial / Q000494:pharmacology; D005838:Genotype; D007094:Imides / Q000494:pharmacology*; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D016133:Polymerase Chain Reaction
D001562:Benzimidazoles; D004271:DNA, Fungal; D005659:Fungicides, Industrial; D007094:Imides; C031000:benzimidazole